Base materials (i.e., materials or structures to be reinforced, such as expanded foams) with woven fabrics or nonwoven fabrics of glass fibers, carbon fibers, organic fibers or the like bonded as skin materials thereon to reinforce the surfaces of the base materials and also, to improve the design features of the base materials have been used for many years. These woven fabrics or nonwoven fabrics, however, require their integration with base materials by using an adhesive or the like, resulting in a need for labor in processing.
With a view to heighten surface durability or rigidity, those making use of FRP as a surface material have been extensively adopted for many years. However, these conventional FRP are accompanied by a problem of inferior processability, because due to use of thermosetting resins in the conventional FRP, the integration of base materials with the FRP requires to adhere FRP sheets on the base materials via an adhesive or to bring woven fabrics or nonwoven fabrics of glass fibers or the like into conformity with surface configurations of the base materials, to impregnate the woven fabrics or nonwoven fabrics with a thermosetting resin monomer and then to harden the thermosetting resin monomer to shape the woven fabrics or nonwoven fabrics.
When an FRTP sheet is used as a surface material, on the other hand, it is a thermoplastic resin that is employed in the surface material. Accordingly, the FRTP sheet is low in brittleness and excellent in handling properties, and by thermocompression bonding, permits integration with a base material, bringing about excellent processability. The FRTP sheet, however, involves a problem in that it can hardly be brought into conformity with the configurations of the base material, for example, upon integrating a unidirectionally long-fiber-reinforced thermoplastic resin by thermocompression bonding.
Another process has also been proposed, which comprises bringing a woven fabric or nonwoven fabric of glass fibers or the like into conformity with the surface configurations of a base material, laminating a thermoplastic resin film on the woven fabric or nonwoven fabric, and then conducting thermocompression bonding. This process is, however, accompanied by problems in that it requires labor in processing and it cannot provide the resulting product with sufficient strength due to inferior impregnating property of the thermoplastic resin.
As a further process, it has also been proposed to use as an L-FRTP sheet a stampable sheet obtained by forming continuous or non-continuous reinforcing fibers into a mat and impregnating the mat with a thermoplastic resin. The stampable sheet is, however, accompanied by problems in that because of a reduction in glass content to provide good resin impregnability, assurance of exhibition of durability or rigidity when used as a surface material requires a large thickness and leads to increases in weight and cost.